When welding collision between Third Person UE4 Mannequin's left foot ball, to left foot in physics tab results in an Engine crash.

UE - Simulation - Physics - Jan 30, 2019

When using a Third Person UE4 Mannequin, Opening the Physics asset tab, and welding the collision between left foot ball, to left foot results in an Engine crash. Additional Note: Using the same ...

Directly opening a modified map asset of a streaming sublevel does not always force it to be reloaded (inconsistent with other map open behaviors)

UE - World Creation - Worldbuilding Tools - Feb 10, 2026

When the level currently being edited has unsaved changes and the user opens a new one, the Editor asks if the changes should be saved. If the user answers negatively, the level asset is reverted to ...

Blueprint CDO contains removed component from parent class

UE - Gameplay - Blueprint - Apr 28, 2015

Blueprint CDO contains removed component from parent class. From the AnswerHub post: "It appears that if a component is removed from the C++ class, the CDOs for all of the blueprints remain unchang ...

Crash on play if a BP uses a ClearInstances node followed by an AddInstance node

UE - Graphics Features - Jul 21, 2017

Crash on play if a BP manipulates a InstancedStaticMeshComponent by using a ClearInstances node followed by an AddInstance node. This is a blocker for the licensee. This is a regression: Working ...

[CrashReport] UE4Editor_UMG!TBaseDelegate<FMargin>::operator=() [delegatesignatureimpl.inl:381]

UE - Editor - UI Systems - Aug 29, 2017

This is a longstanding and common UMG crash that has affected more than 200 users since at least the 4.15 release. User DescriptionsI was working in the UI and undid several last changes in quick s ...

Cannot access private member MarkPropertyDirtyFromRepIndex error when building a nativized blueprint with a replicated property

UE - Networking - May 14, 2020

The following error occurs when building a project that has a replicated variable with the replication condition set to Skip Owner inside a nativized blueprint.UATHelper: Packaging (Windows (64-bit) ...

Wrong calculation of "MaxAllocatedCountEstimate" inside FNiagaraRendererRibbons::GenerateDynamicData()

UE - Niagara - Mar 20, 2026

Starting with UE 5.4, function FNiagaraRendererRibbons::GenerateDynamicData() from file [NiagaraRendererRibbons.cpp] attempts to calculate DynamicData->MaxAllocatedCountEstimate as such: DynamicDat ...

[CrashReport] Assertion failed: GetOuter()==NULL in UE4Editor_Core!FText::IsEmpty

Tools - Apr 17, 2017

This is a top 10 crash affecting many users. It is believed it may be related to the auto listen / reimport feature. The callstack shares similarities to past tickets, such as:[Link Removed][Link R ...

[CrashReport] TOctree<TVolumeLightingSample<3>,FLightVolumeOctreeSemantics>::TConstElementBoxIterator<TInlineAllocator<99,FDefaultAllocator> >

UE - Graphics Features - Oct 5, 2017

This Jira is a continuation of [Link Removed]. This is the same callstack which users are submitting, however the other Jira eventually got specific repro steps which were verified fixed in 4.17.0. ...

Dragging a BP variable into a category can produce inconsistent results

UE - Gameplay - Blueprint Editor - Jan 18, 2019

The drag-onto-category operation is assigning the prettified category name, not the actual category name, resulting in variables that are not actually in the same category, even though they appear t ...